1. Field of the Invention
The present invention relates to a backside illumination image sensor and an image-capturing device.
2. Description of Related Art
The performance of an image sensor at low brightness is often improved by forming on-chip lenses, each in correspondence to one of the photoelectric conversion elements, and illuminating each photoelectric conversion element with condensed light. The backside illumination image sensor disclosed in Japanese Laid Open Patent Publication No. 2009-164385 captures an image as signals generated with light illuminating the back side of a semiconductor substrate, which is received at photoelectric conversion elements disposed in the semiconductor substrate, are output through a read circuit formed on the front side of the semiconductor substrate. In order to receive red-color light with a significant wavelength at high efficiency, photoelectric conversion elements (photodiodes) formed to assure a thickness of approximately 10 μm are disposed at the backside illumination image sensor. The surface of each photoelectric conversion element and the corresponding on-chip lens are set over a short distance from each other and the light having passed through the on-chip lens is condensed within the photoelectric conversion element.